Building A Koi Pond That Is Healthy Starts On The Bottom
Building a koi pond is really not that hard but for some reason “experts” have confused and scared many would be pond builders off. That’s really too bad because building a koi pond is a very doable project. Owning and keeping koi is a very enjoyable hobby too. But where to start?
The secret to successful koi pond design is to reverse engineer it. Start at the bottom and piece by piece plan your koi fish pond and you will have a trouble free pond you will be proud of. Take a scattered approach and you may have nothing but problems. Building koi ponds requires planning and most of all common sense.
Koi are large, messy fish that eat and poop a lot. It all has to go somewhere and that is usually on the pond bottom. So building a koi pond that can be kept clean is important.
Previous articles on koi pond design have discussed size, shape and location of your koi pond. So let’s look at the bottom of your koi pond. Healthy pond bottoms make for healthy ponds. A healthy pond bottom is one where detritus doesn’t build up.
Building A Koi Pond With A Rock Bottom
Many people want to put rock or gravel on their pond bottom. We want to hide the pond liner. Yes it’s hard to resist. It looks so natural. At least to us. But if you do cover your pond liner with rocks or gravel you will regret it and quite likely after a while your pond will crash and your koi will die.
First, koi live naturally in ponds and lakes usually with mud bottoms and usually not in rocky streams. So a rocky bottom really isn’t natural. If you look at a koi it has barbs very much like a catfish. They are designed to probe around in the mud and find food.
Streams, ponds and lakes are not a closed system like a koi pond. Water is always moving. Waste is carried away or absorbed by the bottom and doesn’t build up. Ponds may or may not have as much movement. But both streams and ponds have one critical thing a man made pond lacks. They have porous bottoms to help process waste.
Regardless of your method of koi pond construction your pod bottom will be sealed and impervious. What goes in stays in. Rocks in a koi pond will be a place where detritus and uneaten food will build up. It will be a place where anaerobic bacteria grow and a potential source of disease for your koi. This is not a healthy koi pond design.
Building A Koi Pond The Old Fashioned Way
When koi keeping was in it’s infancy under-gravel filters using rock were tried. Building koi ponds using these filters was soon abandoned. They clogged and either became anaerobic or nitrate factories. Ponds suddenly crashed and fish died with no warning. They were patterned after aquarium under gravel filters.
Interestingly enough these are rarely ever used in aquariums any more for the same reasons. Cleaning the gravel in a 20 gallon aquarium is not the same as cleaning it in a koi pond with thousands of gallons of water and tons of gravel. I hope you will not put rocks in your pond because if you do you will regret it down the line.
Building A Koi Pond That Really “Rocks”
Successful koi pond building begins with a smooth and bare bottom. Your waterfall or outlet should be on one end and your skimmer should be on the opposite end. Your pond bottom should slope about 1/4 bubble from your waterfall down towards your skimmer. At the same time it should make a wide vee looking at a cross section. So everything will move towards the center and down to the low end of the pond.
Use Bottom Drains When Building A Koi Pond
At the low end there should be a bottom drain to pick the waste up. Some ponds will have more than one depending on size. My pond has 2 drains. At the low end I constructed a sunken area to act as a sump and placed my drains in there. It is amazing what they pull out!
By using bottom drains and a proper pond bottom your pond and your koi will stay healthy and your maintenance will be greatly reduced by building a koi pond the right way.